We were two weeks into our car-free experiment when I was seized by my inner bulldog. It was raining—downpouring in gale-driven sheets, actually—on the morning of the Waring School convocation, a lovely ritual at which incoming students are welcomed with speech and song and string ensembles.

My wife, Patty, was wearing a crisply ironed dress, 14-year-old Celia a summer skirt, and 12-year-old Henry a blazer and tie. Me? I was in sweatpants, sulking upstairs. Rather than riding bikes to school and changing, as the spirit of our campaign so plainly suggested, the entire team had coalesced behind Patty, who had proposed an alternative: It's raining; let's call someone and get a ride.

It sounds like a minor logistical disagreement, but it quickly became serious. Patty thought I was bullying the kids, like the utopia-or-bust Harrison Ford character in The Mosquito Coast. I thought she was copping out and not giving our car-free experiment a true go of it. Voices were raised, harsh words exchanged. It seemed then that my neighbor had been right. He'd said it would be two weeks—at most—before it all went to crap. I had laughed. But with rain raking the gutters, the basement filling with water, and my family headed out the door without me, I could not deny it.

Two weeks it was.

Prelude: Year of the Bike

It had all begun innocently enough.

Late last summer, fuel prices were soaring, begetting a belt-tightening reflex that seems almost quaint compared with the economic hellfire Americans now face. The troubles in Iraq provided a continual reminder that fossil fuels come from faraway countries with ghastly human-rights records. I'd recently ridden a Critical Mass, tagged my mountain bike with a "000 9/10th per gallon" sticker, and one-clicked the Amazon title How to Live Well without Owning a Car.

When gas topped $4 a gallon at the Hess, I felt the overwhelming urge to excise the automobile from my life for a while. I pitched the idea to the family, and they all agreed to travel exclusively by bicycle (or walk, or take public transportation) for one month, as a sort of experiment in car-free living.

I was not alone in my blessed-be-the-bicycle awakening—especially on that all-important, campaign-beloved place known as Main Street. Bikes for everyday transportation exploded last summer. Noncyclists and lapsed cyclists alike settled onto saddles. Susan McLucas, the so-called "bike whisperer," sold out classes at her Bicycle Riding School, in Somerville, Massachusetts, where ungainly adults lurched and stumbled after mounting two wheels for the first time. Old Peugeot UO8s and Raleigh Grand Prixes emerged from basements like once-a-generation cicadas, teeming and proud. Bicycle commuting even caught fire in places like Greensboro, North Carolina, and Little Rock, Arkansas.

"Higher gas prices have created a cycling-commuter boom," Trek CEO John Burke wrote his stockholders, reporting that August sales at 50 bellwether shops were up 23 percent from a year ago. Giant's sales figures in the first half of 2008 rose 24 percent. A Portland-based blogger sounded ready to curl up and die happy when he saw Dutch-style city and work bikes sprinkled around the Interbike trade show in Las Vegas. "Utility is the new carbon," he wrote.

The bike was becoming something almost indispensible, a utilitarian piece of everyday middle-class weaponry meant to combat fuel-price inflation. But in a more lovely and rebellious way, I told Patty, the bicycle was a way to stick it to The Man Himself. Nobody was going to build a retirement nest egg out of the money saved by riding a few more miles each day. The greater incentive was the act of economic disobedience: "Screw you, Exxon Mobil: I'm riding today." In August, the month prior to my family's campaign, the government reported fuel consumption and car use dipping for the first time in a generation. Transit officials said bike-rack use on city buses was soaring. Something beautifully subversive was happening.

I wasn't going to be the guy who missed one of those iconic rising-ups that define a generation. There were a few logistical challenges, but we live close to the kids' school (1.6 miles), Patty's commuter train (one mile), downtown Beverly, Massachusetts (less than a mile) and two sizeable grocery stores (a mile).

I imagined my kids' children asking one day: Where were you during the bicycle revolution?

My family and I took to the roads during the second week in September. I hadn't so much asked for family input as declared a start date.

Our new bike life would slow things down, make us see the world in deeper, more enriching ways. That was what I said. I didn't mention that as a freelance writer, I had nothing but time. Patty, a full-time editor multitasking her way through a half-dozen book projects, did not. She worked in Portsmouth, New Hampshire, 48 miles away. For her, the notion of traveling on hard seats at 10 mph instead of 50 made my dream experiment look more like a commuting nightmare.

The kids played on soccer teams that held practices 8 miles from home. There were visits scheduled with relatives in Connecticut. We weren't some crunchy organic family living off the grid and heating our post-and-beam with a pellet stove, Patty reminded me. We left lights on and took marathon showers. Sometimes, when the dog needed a walk, I loaded him into the minivan and drove the flat eighth of a mile to the park.

But perhaps the biggest issue was safety. Beverly, a small city 28 miles north of Boston, isn't a destination like historic Salem or beachy Manchester-by-the-Sea. It is a city of nail salons and Dunkin' Donuts, but also has a gorgeous old movie house where the doormen dress in black tie on Saturday nights. There is something here. "Has possibility" is an often-repeated phrase—but what most notice first are all the cars coursing along the main drag, trying to get somewhere else.

Despite my many assurances about the safety of riding, Patty wasn't convinced, citing street junctions with jarring railroad tracks and the aggressive drivers who buzzed too close, edging her toward a curb or a parked car. "If I wasn't scared, I'd feel a lot better about this," she said.

On one of our first days, after a soccer game, our whole family rode home together. It wasn't at all like Robert McCloskey's Make Way for Ducklings. Patty fought her bike's gearing, and Henry wished he had the zippy hybrid electric loaner his sister was riding. Celia distractedly wandered from one side of the road to the other, indifferent to motorists trying to predict her next swerve. The narrow, dark road consisted of 1.6 miles of blind curves, ditches for shoulders, a three-way railroad-track crossing, a largely unobserved stop sign and several teenaged drivers looking to break land-speed records for going from one side of Beverly to the other. Now I, too, was terrified. I thought longingly of the fortress-like confines of our steel-sided, seat-belt-filled automobile.

I was reminded Beverly lacks any real bike culture. There are no 200-plus miles of new bike lanes like in New York City, and no ride-to-school initiatives like in Boulder, Colorado. Nor are there bike shares, bike garages or bike czars—all of which are new features in our most forward-thinking cities. When World Carfree Day dawned on September 22, nobody was the wiser. Beverly is like many small cities, a little too overwhelmed to be forward thinking. We would have to be guinea pigs, relying on frontier individualism. I would keep us humming with old-fashioned "attaboy" enthusiasm and assorted incentives.

I tried to get bikes that everyone liked. I retrofitted an old Jamis mountain bike into a town singlespeed with a rack for Henry. I borrowed a friend's Trek tandem for shuttles to practices and sleepovers, an Xtracycle long bike for grocery runs, and a foldable model in hopes of convincing Patty to try a crazy multimodal commute involving southbound trains, northbound buses and a schleppy 10 miles of riding in between. While waiting for the foldie to arrive (and Patty to warm up to this scheme), she arranged to bum rides from a coworker.

The kids took turns commuting to their grades-6-through-12 school on the Giant electric hybrid. The "Twist" was a monster hit. Lazy seniors rode it to their parked cars to pick up after-school sports gear; middle-schoolers snuck aboard and bombed around the pickup circle. Even Patty got hold of it for a dinner ride downtown. She felt safe, and the lumpy Beverly streets didn't distract her. "Can we keep it?" she asked sweetly.

The Xtracycle cargo bike is popular in bikes-will-save-the-world places like Portland, Oregon, and Berkeley, California, but in our town it was the oddball equivalent of a blue-footed booby showing up on the seawall. I christened it by stuffing its side satchels with a cooler, beach chairs and a picnic dinner. You can double a passenger on its skateboardlike wooden deck. Celia and her friend Maggie took giggly turns taxiing one another, and when I rode down the big hill near our house, Henry stood up, balancing with his hands on my shoulders so he could absorb the breeze and view. I swear I heard him hoot. We were living the dream and breaking all the rules.

Our first week, we saved 48 car trips, I figured, eliminating 350 car miles through a combination of bikes, public transit and car shares. I told the kids we'd spared the atmosphere 350 pounds of CO2 and dropped $71.76 into a plastic Mr. Beer keg container. The cash, I explained, represented the amount we'd saved by replacing car miles. (I multiplied 110.4 cycling miles times 65 cents a mile, the American Automobile Association's estimate for what it cost to drive a car at the time; I didn't count public transit or car-share use.) To clarify the reasons a keg had become the centerpiece of our dining-room table, I decorated it with bike-transport-advocacy stickers that said things like, "I lost 3,500 pounds in one day!"

Patty rolled her eyes, but I was pretty sure this was the best thing we'd ever done.

Still giddy about our first week, I registered our efforts with Clif Bar's 2Mile Challenge. Caught up in the spirit of things, Clif had challenged participants to ride bikes for trips 2 miles or less (almost 40 percent of all urban travel in the United States fit that description). I mistakenly plugged in incorrect numbers and immediately found my name at the top of the international do-gooding list with an obviously fraudulent 1,000 miles per week. "What's the world coming to," I imagined a hawkeyed blogger despairing, "when people pretend to ride their bikes for the good of Planet Earth? For shame, Balf family."

I sensed a different vibe from our neighbors and friends: Call it wariness. One parent told me she was having trouble sleeping at night wondering if I would subject my son to riding stoker on the 8-mile trip back from soccer practice—most of it on a dark, narrow road. Others seemed mildly defensive because they were driving. They pressed us on our protocols.

"You can take a train?" probed a school-faculty member. "What about a car—can you mooch a ride?" A lawyer friend cross-examined our grocery strategy: "Are you getting them delivered? Just because it's not your carbon footprint, it's still a footprint."

I answered that we took trains, even car rides if they were offered, but no grocery deliveries. Most practice days, I'd get Henry a ride home with his coach and ride the tandem home solo. The beauty of the experiment was that we set our own rules. I didn't want to be dogmatic; I just wanted to keep to the spirit of the mission.

That was what I said. But as the second week passed, I became increasingly set in my new ways. I didn't want to be in a car, pretty much no matter what. I was not only reading the late philosopher Ivan Illich, but also understanding him. I liked seeing my tally counts go up. I even began padding the stats, adding recreational miles to commuting chores to bump up the totals. I ran unnecessary errands, determined to beat our Week One record of 15 car trips saved in a single day.

In this narrow place, I ignored some uncomfortable realities. Like our great inflating grocery bill: With all the exercise, I was eating like a college lineman. Later I read about a University of Pennsylvania study that used probability theorems to challenge the widely held notion that trading cars for bikes helps the environment. In actuality, it was a wash, argued the author, Karl Ulrich. The problem is that heart-healthy bike riders live longer and eat ferociously. We are as big a drain on the world (in our own way) as fossil-fuel-driven machines, Ulrich contended.

Then there was my attitude. I wasn't getting all laid-back, as you'd expect from a guy taking part in what someone dubbed the Pleasant Revolution. Instead, I was growing intolerant of motorists. Their buzzing, pushy presence annoyed me. I bought the family provocative "One Less Car" hoodies. "How about waiting?" I hollered when a driver plowed past, refusing me a left turn in downtown traffic. I was balancing $150 worth of groceries on my long bike and had a rented Rug Doctor strapped to the rack. I looked back at Henry, riding right behind me, and saw him cringe. "Sorry," I said.

Still, these things I could overlook. We'd established a routine, and I would soon put another $35.10 in the old Mr. Beer belly.

What I couldn't ignore as the second week came to a close was the weather. We'd had almost two weeks of perfect, sunny September days. When the rain began on Thursday, I simply had the kids throw on slickers and use plastic grocery bags to cover backpacks. I rode with them to school, for solidarity, but when we pulled up, an upperclassman looked at them, then me, and said half-accusingly, "How could you?" Our family experiment had suddenly gone from cool and hip to strange and compulsive. I had gone from the dad everybody thought was fun to the bike Nazi with uncertain employment.

Yet it would get worse, much worse. The rains picked up intensity on Friday and were jungle-torrential on Saturday. Area creeks crested their banks. The morning of the convocation, I got up early and rode to the grocery store in the watery blitzkrieg to set a stoic example. "Not too bad out there," I cheered on return. "We'll be good."

Only nobody was buying it. Patty was fixed on not riding and the kids, while wanting to stay with the experiment, weren't objecting to the idea of a warm, dry car. When I grumped about everyone giving in, Patty accused me of making this a test: If we rode through the storm we passed, and if we didn't we failed. "We're trying real hard," Patty said, "but if you don't like this family maybe you should find another one."

Fine, I said. Take the car ride. I announced that I would meet them there. I rode, and Patty and I sat in different rows as the string ensembles and skits and inspiring speeches (many of them about overcoming some torturous personal flaw) played out.

When the event was over—the rain falling heavier than ever—I exchanged my commuter for a mountain bike and rode in miserable solitude for two hours in the submerged woods. I was searching for catharsis and wisdom, but the voices in my head kept screaming the same thing: They're just not that into this. I recalled that the previous day, the kids had grabbed a lift home from school and I ghost-rode their bikes for them. That was a symbolic ride: me, my bike and an abandoned mount.

When I got home, I announced my decision: Let's end this thing, I said. We were doing this because I wanted to, not because the family did. We'd stopped driving our cars for almost two weeks; that was respectable.

The three of them looked at me in shock. All of them, Patty included, wanted to keep riding. "We told everybody we were going to do this for a month," Celia said. "We can't stop now."

"Way to go Balfs!" hollered a parent at Celia's soccer game, seeing Patty and me pulling in on a tandem. We probably hadn't done something that transparently goofy together since the kids were born. There was an injury timeout on the field when we arrived, allowing our daughter's entire varsity team to observe this goofiness. I heard Erin, the captain, exclaim, "Celia, your parents are so weird!" But she said it in that teenager way that suggested good weird.

As the days turned to weeks and we kept riding, I couldn't help but notice friends riding to school who we'd rarely seen on a bike before. "How did you get here?" a kid asked his van-driving mom one day as we chatted near the school entrance. "Oh, by bike," she said nonchalantly. "Really!" her son screamed.

Our once-tense dynamic with the community—the "are you trying to be better than us by riding instead of driving?" vibe—had morphed into "why don't we give it a go too?" Beverly hadn't become Portland, Oregon, with its bike-riding mayor and its boulevard-style "complete streets." But still.

Since the convocation crisis, things had changed at home too. One evening I came home after tandem-shuttling Henry from a faraway soccer field to find a note on the kitchen table: Patty had walked to the school for a curriculum program. She could've asked for a ride.

The day before, when it was cold and wet, she'd snapped photos as the kids cycled off in ski jackets, winter gloves and balaclavas. We need to remember this, she'd said. The sentiment surprised me, but Patty's evening walk was better still. "We should do a school meeting about this," Celia said. This thing we were doing was extraordinary, she said. Actually she called it "pretty legit," which I think is the same thing.

Unable to travel far, we focused on our house, the neighborhood, each other. Our world shrank. I saw disquieting things, like our chimney crumbling, but also noticed the late-afternoon trill of wind chimes hanging from the catalpa tree. My neighbor, the one who had predicted the two-week deadline for family Armageddon, found me on our porch roof touching up the second-story window trim. "How's my favorite non-internal-combustion-engine-using family doing?" he mischievously probed. Looking down, I could truthfully answer fine, just fine.

Our newfound inward focus was unfortunately not perfect. Amid all the riding, someone finally realized that our pet fire-bellied toads, Hopper and Hoppy, hadn't eaten for a long time. I hurried off for a box of live crickets, but when I returned I saw Hopper, but no Hoppy.

I could only assume the worst. While we were off changing the world, Hopper was reduced to eating?Hoppy. It had started off as a nice little experiment, but now there was blood on my hands. Feeling penitent, I fed the dog and cleaned the cats' basement litter box.

Week 4: End of the innocenceCar trips saved: 38Car miles replaced by bike: 72Single-day high/low in utility bike miles: 23/2

We hit several milestones as the month wound down. One day we used five different bikes to eliminate 10 car trips. On another I traveled with three bikes simultaneously: I ghost-rode the long bike back from the kids' school, with the folding bike strapped to the deck. "Wow, a bike on a bike being driven by a bike," said a bewildered student.

We were approaching the 150-car-trips-saved mark with no injuries and only poor Celia stacking. She'd been doubling a friend on the rack; both were shouldering book bags and soccer duffles. They skinned knees and elbows, and were delivered to our front door in an upperclassman's Suburban. "I'm okay," Celia said, "but I hope I didn't kill the bike."

By the last week, actually, we had a mounting number of broken spokes and flats. A crankarm fell off Henry's singlespeed; a neighbor with good intentions tried to hammer it back on, which temporarily reduced our fleet by one. I began to grasp the time involved in maintaining six bicycles. Between the hassles, an energy-sapping head cold and a snap of arctic weather, I found myself for the first time looking with real longing at the cars fixed to our driveway.

I also began thinking about what this had meant. When you ride rather than drive a half-mile to the store hoping to bring about change, you're putting faith in the transformational possibilities of millions of people doing the same. The act in itself is not necessarily gratifying. When my neighbor wanted to do something special on his 39th birthday, he decided to ride for his annual Whopper indulgence at Burger King. He was unmoved: "I saved like 39 cents. Why bother?"

Of course, the real value comes incrementally, a year or 10 years into the future. I calculated that if everything stayed the same and the kids never left home, we'd save $31,000 while sparing the planet 40,000 pounds in CO2 emissions in our lifetimes.

This made me feel better, but it didn't fully explain the value of what we'd done. I couldn't easily quantify the intangibles. The lifestyle made me happier and more hopeful. I liked the collective act of reinvention. And unlike my neighbor, I found the simple act of riding together electrifying in small ways. On various rides—home from soccer practices, or when I picked them up after sleepovers—I heard about Celia's first high school dance and listened in as Henry, riding stoker, absently hummed a song learned in French class.

Even off the bikes, good things happened. We started turning off lights and recycling cereal and muffin boxes. As one expert explained it to me, biking is like a gateway drug to greener living. We relied on the community, accepting more and I suppose asking more. My brother, who dropped by with Trader Joe's peanut butter cups and dipping cookies, likened us to pleasant elderly shut-ins.

Even our dog's life changed. He didn't fit into the Jamis's milk crate, so we walked to the park or the beach. He marked up new territory. Canines throughout Beverly understood something new was afoot.

Coincidentally, just as our month ended, the grim prompt to our adventure began to vanish. Gas prices began dropping and people resumed driving as colder weather took hold. Bike people with cultural-reinvention plans were back on the outside looking in.

I remained hopeful. The Peugeots and Raleighs might disappear again, but probably not to the remote parts of basements. And when they return next time, they will find, by virtue of the rather extraordinary number of cycling-related improvements in 2008, more in the way of paths, traffic laws and overall support than there'd been before. By then, Google maps might even have its "bike there" link up and running.

On our last night, I arrived by bike at midnight to escort Celia home from her babysitting job. She came outside laughing. The parents, peering out at my silhouette, had suspected I might be a boyfriend angling for a dangerous rendezvous. "Who in the world is that?" they had demanded.

It's just my dad, she'd said. On a bike.

I held out a few more days, waiting for Patty to make the first car trip. But I succumbed not long after.

Our family didn't go into a road-tripping frenzy, gorging on fuel like shipwreck survivors newly exposed to food, as my brother had predicted. The kids kept riding to school while the weather allowed. Patty asked repeatedly about the electric bike. And nobody seemed to care that my grand incentive scheme—the one involving the Mr. Beer keg—had tallied about $215. I'd promised the money to a family present, but when nobody asked I just pocketed the cash and figured I'd make it up to everyone at Christmas.

We didn't change the world—or even our neighbor's mind—and the savings were relatively small. In the end, none of that mattered; the money wasn't the point. What mattered was we did it, and we felt pretty legit.

A year later, Todd Balf is still trying to convert his next-door neighbor.